My daughter and her friend recently gleefully posed me a riddle: There are two towns, Liestown, where the inhabitants always lie, and Truthstown, where everyone tells the truth. A man from one of the towns says: “I am from Liestown” – do you believe him?

Although continuing exchanges about republican criminality exhibit superficial similarities to a debate, the discussion is taking place in two distinct languages pertaining to irreconcilable perceptions of reality. Politicians such as Michael McDowell believe that, as defenders of the rule of law, they speak to the highest form of public morality.

But republicans, in their own minds, also inhabit the high moral ground. They believe that years of combating injustice under the banner of the Irish nation’s struggle for integrity confer on them the right not merely to engage in what Michael McDowell insists on calling “criminality”, and to deny such involvement in order to prevent him putting them in jail, but to refuse the idea that the term “criminality” is appropriate at all.

There is a political background to this. The Belfast Agreement offered, in theory at least, the opportunity for all sides to stand down traditional positions and strategies, inviting each to concede something in the interests of a settlement. You could argue, as I did at the time, that unionists acted in bad faith by seeking retrospectively to turn the agreement into a republican surrender. But republicans also refused to stand down their core rationale, based on their sense of being beleaguered in a state run by their political enemies.

What was being offered to republicanism in the Belfast Agreement was not just power- sharing but co-ownership of a peaceful, democratic society. You might say that the true act of decommissioning required of republicans in return was not of bullets, bats and rackets, but of victimology, the standing down of the sense of grievance that had been their driving force.

The republican leaders ultimately lacked the confidence to accept that challenge, and instead encouraged their constituency to cling to a historic sense of victimhood. Their big mistake was believing that the duplicity of their opponents took all the pressure off them – that as long as unionists continued to behave as unionists always had, the republican culture of grievance-based subversion could continue. The IRA could go on, the rackets could go on, the “community policing” too – and, more than that, the nod and wink, the “aren’t we the bould Fenian boyos” mentality, could continue.

Republicans have misunderstood the motives of many who supported their right to a voice, misreading a desire for peace as an endorsement of their overall demeanour and ethos. Many of those who worked for their inclusion do not think the Provisionals anywhere near as cute, clever, sexy, bould or even Fenian as they appear to think themselves. There is widespread repugnance of the Jesuitical contortions they have achieved to redraw lines between right and wrong, enabling a settled justification of actions incompatible with democracy.

And there is a growing perception that the corruption of idealism within the movement has vindicated the most apocalyptic prophecies of the Provisionals’ most virulent opponents.